1. Field of the Invention
This invention relates to a water faucet for a sink or washstand, particularly to an automatic water faucet of the sensor type and how the faucet is attached to the sink.
2. Prior Art
Conventionally, water faucets are attached to sinks (or washstands) as follows: First, a hole is bored near the sink. Next, the base of the faucet is lowered into the hole. A nut is then screwed onto the screw formed on the outside of the base of the faucet and tightened until the facet flange presses tightly against the sink. Then, a tap is attached to the pipe providing water to the sink and a further pipe is connected between this tap and the faucet.
Such taps are attached to allow the water to be turned off when the faucet is being repaired while still allowing the other taps in the house to be used, thereby preventing other users of the water in the building from being affected.
FIG. 18 shows a conventional domestic-use faucet, and indicates the mouth 1, the shut-off valve 2, the attachment flange 3, the threaded portion 4, and the connecting portion 5. This faucet is fixed to the sink by a nut 7 screwed over a washer onto the threaded portion 4. The water supply pipe is connected to the end of this.
FIG. 19 is an explanatory view of a conventional sensor type automatic water faucet attached to a sink. The structure of this faucet differs from that of the conventional faucet as shown in FIG. 18 in that a sensor 8 for detecting hands is provided near the mouth and an electric cable 9 with a connector 10 is provided for connecting the sensor with the controller. Since this water faucet is an automatic type, there is no water shut-off valve 2 as shown in FIG. 18. The electric cable 9 is enclosed in a flexible metal pipe (spiral tube) to prevent it from being cut in an act of vandalism.
The washer 6 is not flat but of a conal shape. This cone-shaped washer 6 is used to allow the electric cable 9 to pass through the washer 6 when the nut 5 is tightened. Reference numeral 13 indicates the thickness of the sink. The O ring 11 serves to prevent water leaking through gap between the mouth and the sink. Although it is not indicated here, an O ring is also used in the faucet in FIG. 18.
FIG. 20 shows a conventional sensor type automatic water faucet with the sensor and controller attached. The controller section 14 contains an electric circuit for processing the signal from the sensor, an electromagnetic valve for turning the water ON or OFF and a battery which supplies power to these components. The inlet 15 for the electromagnetic valve provided on the underside of the controller section 14 is connected to a pipe 17 leading to the water line by a cap nut 16.
When replacing an ordinary faucet with an automatic type, in most cases, the old faucet is replaced with a faucet with a built-in sensor. An electromagnetic valve is then connected between the faucet and the water shut-off valve, and the controller which processes the signal from the sensor and drives the electromagnetic valve is attached to the lower side of the sink.
In many battery-powered automatic water faucets, the battery is housed within controller section. The controller, electromagnetic valve and sensor of such faucets are usually housed in water-proof structures to prevent entry of water.
When the controller is attached to a wall, it is secured by screws. However, if the wall is a tiled surface, holes have to be drilled in the tiles, which is time consuming and the tiles may also break. For this reason, some automatic water faucets are configured so that the electromagnetic valve and the controller portion are integrated. Such faucets is connected between the faucet and the water supply, or is connected to a water stop valve.
Such configuration has been made possible because the mechanics of the such water faucet have become compact and much lighter. This reduction in size is the result of smaller batteries (made possible because of lower power consumption), the development of compact batteries and the miniaturization of the electric circuits in the controller with greater use of integrated circuit.
Many automatic water faucets are configured so that an electromagnetic valve opens to release water when a hand is detected near the faucet. For this reason, the detector is located near the mouth of the faucet to set to cover the area below the mouth. The signal from the detector is transmitted to the controller by a cable. The electric cable connected to the detecting section passes through the inside of the spout and emerges from the water supply pipe. A connector is attached at the tip of the cables. This connector is connected to the receiving connector which leads to the controller.
The holes in sinks for passing through faucets do not have to be adjusted for sensor faucets as sensor faucets are the same size as ordinary faucets. Often, the faucet hole is larger than the water supply pipe.
To allow for easy connection of the electric cable to the controller, the electric cable is made longer than the section of pipe extending below the faucet in which a screw thread has been cut. When attaching the faucet, the electric cable is first passed through the hole in the sink for attaching faucet from the upper side of the sink. The threaded section of pipe is then passed through the same hole. The special washer for allowing the cable to pass is then screwed onto the threaded section of pipe to firmly hold the faucet in place. A nut is then tightened over the top of this washer. If the special washer is not used, the cable would get in the way, which would prevent the nut from being sufficiently fastened. Accordingly, it is necessary to allow the electric cable to pass between the space provided by the thickness of the special washer. Once the faucet has been fixed to the sink it is connected to the electromagnetic valve.
As the result of the configuration as stated above, when an ordinary manual faucet is exchanged with a sensor type faucet, the manual faucet first has to be removed. This work can be difficult and time-consuming as most sinks are installed up against a wall, with little or no gap between the sink and the wall and positioned near the floor.
Moreover, because of such attachment structure, the exchanging of an old faucet with one of new design or the replacing of a broken sensor is never an easy operation.
In addition, there are many instances where design of the neck portion is chosen in accordance with the interior and/or atmosphere of the room. This means that the faucet is often shipped from the factory with the neck unattached. Thus the ratio of factory-assembled faucets cannot be increased.